1. Field of the Invention
The invention relates to windshield wiper assemblies.
2. Description of the Prior Art
Windshield wiper assemblies are known comprising a wiper arm and a main yoke. The main yoke includes a recess adapted to receive the wiper arm. The wiper arm is connected to the main yoke by means of a connecting element and is pivotally locked with a pin secured between the side walls of the main yoke. In these assemblies, the wiper arm extends above the supporting yoke system resulting in a relatively large overall assembly height.
In other known windshield wiper assemblies, the wiper arm is positioned laterally of the supporting yoke system and is suspended on a pivot pin laterally projecting on the wiper blade yoke system. These assemblies are preferred for styling reasons, and because a low overall height is obtained which results in the assembly having a lesser likelihood of lifting from the windshield when the vehicle is moving at higher speed.
German laid open print U.S. Pat. No. 2,105,775 shows a wiper arm with a U-shaped wire yoke. The free ends of the yoke each include a coupling member for attaching the wiper blade. The web of the yoke is fixed on a link. The wiper arm in this assembly is positioned above the supporting yoke system of the wiper blade.
In all these prior assemblies, the wiper blade has to be provided with a pivot pin on which the coupling member to the wiper arm is coupled.
For wiping efficiency, it is advantageous to maintain the wiper blade perpendicular to the windshield so that the edge of the wiper lip wipes over the windshield at an angle of about 45.degree.. In prior assemblies having the wiper arm centrally attached between the side walls of the main yoke, it is difficult to obtain these relationships. The combination of the driving force on the wiper arm and the frictional force between the wiper lip and the windshield creates a pitching moment on the connection between the wiper arm and the main yoke such that the wiper blade tilts.